Heating system



y 1940- G. D. BOWER 2,207,083

HEATING SYSTEM Filed Dec. 11, 1937 2 Sheets-Sheet 1 INVENTOR 7 George D.Bower ATTORNEY July 9,1940. G, BOWER 2,207,083

HEATING SYSTEM Filed Dec. 11, 19:57 2 Sheets-Shet 2 I I06 I05- 95 Fig.3

INVENTOR George D. Bower ATTORNEY ?atented July 9, 1940 UNITED STATESPATENT OFFICE HEATING SYSTEM George D. Bower, Columbia Heights, Mimn,as-

, signor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn.,a corporation of Delaware Application December .11, 1937, Serial No.179,318

Claims.

During times when the space temperature is at a high enoughvalue, andthe dampers are in their draft retarding positions, it may be necessaryto add fuel to the furnace. If this is done while the dampers are intheir draft retarding positions, there is a danger of smoke and gasesissuing from the firing door of the furnace. In order to eliminate this.danger, the check damper should be closed so that the draft through thestack will be increased, and to get the best results, the draft dampershould remain closed in order that all the air entering the furnace will39 enter through the firing, door, thus reducing to a minimum thepossibility of any smoke or gases issuing from the firing door,

I achieve .these results in my invention by providing means whereby thedampers may be 5' manually moved from a draft retarding position to anintermediate firing position wherein both dampers are closed, and meansfor causing the dampers to return to their draft retarding positionsshould they be manually moved beyond their firing positions to aposition wherein the draft damper starts to open. Means are alsoprovided for insuring that the dampers will automatically be returned totheir draft retardin positions, should the attendant neglect to do thismanually withthe result that the furnace temperature attains anexcessive value.

It is often desirable to utilize the system for circulating unheated airduring hot weather when there isno fire in the furnace, in which casemeans are provided for causing the fan to operate when the temperatureof the space is above a predetermined value. Provision is made fornormally maintaining. the dampers in their draft retarding positionsduring this time, from which positions they may be-manuaHy moved todraft 4 producing positions should it be desirable to burn trash in thefurnace to supply heat to the space during an un'seasonable cold spellfor example.

Means are provided for causing the dampers to 5 return to their normaldraft retarding positions upon the attainment of a predeterminedhightemperature in the heating chamber, in which position they will remainuntil manually moved again.

M It is an object of my invention to provide an improved control meansfor a furnace provided with draft and check dampers for controlling-therate of combustion in' the furnace.

It is a further object of my invention to pro vide a novel dampercontrol system for a warm 5 air furnace combined with a circulating fanthat may be automatically operated in winter or summer to circulateheated or unheated air through a space to be' controlled. v

More specifically, it is an object of my inven- 10 tion to provide 'asystem for causing the draft dampers of a furnace to. move to draftretardin or draft producing positions according to the temperature of aspace being heated, in combination with means whereby the dampers may 15be manually moved to an intermediate position for firing purposes, andmeans whereby they will be automatically returned to draft retardingposition should they be moved manually beyond the intermediate position,in which position the 20 check and draft dampers are both closed.

Other objects will become apparent upon a study of the specification,claims and drawings, in which like parts are represented by likereference characters, and in which: 25

Figure 1 is a schematic view of my improved heating system;

Figure 2 is a perspective view of the damper operating arm assembly; and

Figure 3 is a view in crosssection of the damper 80 arm I! in aclockwise direction will cause damper I 6 to close and damper I5 toopen. It will be noted that cable I8 is provided with acertain amount ofslack so that damper I5 will be closed 45 before damper I 5 will startto open, thus permitting both dampers to be closed at the same time.

For circulating air through the heating chamber of the furnace Ill andthe space or spaces to be heated, a blower 25 is provided, this blowerhaving a return duct 26connected to the blower inlet, the outlet of saidblower being in communication with the heating chamber of the furnace. Amotor 21 is provided for operating the blower '25and is connected tosaid blower by u 30 of the motor and blower, respectively. Motor 27 isprovided with terminals 3| and 32 which are connected to a source ofpower in a manner to be later explained.

Mounted in the heating chamber of the furnace is a bimetallic element 23connected at oneend to a rod 24 which is in turn connected toswitches'33, 34, and 35, respectively, to cause the same to be tilted inresponse to temperature changes in the heating chamber in a well knownmanner. Switch 33 includes a mercury element 36 and contacts 31 and 38,these contacts being normally open as shown. Switch- 34 includes amercury element 40 and contacts 4| and 42, this switch being normally ina closed position, and switch 35 includes the mercury element 43 andcontacts 44 and 45, said contacts being normally open. Upon theattainment of a predetermined temperature in the heating chamberbimetallic element 23 will cause switch 33 to be tilted to .closedposition, upon the attainment of a higher chamber switch 35 will betilted to closed position.

Mounted in the spaceto be heated is a thermostat generally indicated bythe reference character 50, this thermostat including a bimetallicelement 5| and arms 52 and 53 carried thereby. Fixed contacts 54 and 55cooperate with the arms 52 and 53, respectively. Arm 52 is made flexibleand is arranged to engage contact 54 before arm 53 engages contact 55.When the temperature in the space drops to a low enough value afterengagement of arm 52 with contact 54, the arm 52 will be caused to bendand permit arm 53 to engage contact 55.

Controlled by the thermostat 50 is a relay generally indicated bythe'reference character 60, this relay including a coil 6I, an armature62, and switch blades 63, 64, and 65. A fixed contact 66 cooperates withthe switch blade 63, contacts 61 and 68 cooperate with the switch blade64 and contact 69 cooperates with the switch blade 65. When the relay isdeenergized, blade 64 is in engagement with the contact 68 and theblades 63 and 65 are out ofengagement with their respective contacts.Upon energization of the relay 60, blades 63, 64, and 65 move into imotor 10 is provided, this motor including an armature 12 and fieldwindings 13 and 14. Winding 13 is termed a lifting winding, energizationof which in conjunction with winding 14 causes the damper arm I1 tomovethe dampers to a draft producing position and winding 14 is aholding winding andfunctions to hold the damper arm in its draftproducing position as long as this winding remains energized. The arm I1is mounted on a shaft 15 which isconnected to the armature 12 throughsuitable reduction gearing 16.

Referring more particularly to Figures2 and 3 it will be noted thatshaft 15 is mounted through bearings H and 11 which are in turn mountedin stationary walls 18 and 19. Fixedly mounted on the shaft 15 is adriven gear 90 from which projects a pin 8i. Mounted in the wall 18 arepins 82 and 83 which are arranged in the path of movementof the pin 8|and serve to limit the amount of rotation of the gear 80 and accordinglyof the shaft 15. To one end of the shaft 15 source of power (not'shown).

means of a belt 28 passing over pulleys 29 and is rigidly connected anarm 65 which is normally biased in one direction by a spring 86, thisspring causing the shaft 15 to rotate in a direction to cause arm Ill-tomove in a counter-clockwise direction as viewed in Figure 1.

To the opposite end of shaft 15 is connected the arm I1. Fixedly mountedon this end of the shaft is a clutch member 90, said clutch memberincluding a disc portion 9I and a cylindrical portion' 92 having aflange 93 at the inner end. Pins 94 are provided in the disc portion 9Iand these cooperate with apertures 95in the arm I1. Arm I1 is arrangedfor slidable movement on the cylindrical portion 92 of the clutch member90 andis biased towards clutching position by a spring 96 which ispositioned about the cylindri- .cal portion 92 and between the arm I1and the I flange 93 as clearly illustrated in Figure 3. Concentricallymounted with respect to the cylindrical portion 92 is a cylindricalportion 91 rigid with the arm I1 extending inwardly from the arm I1,this cylindrical portion being provided with a cam surface 98.

When the arm I1 is in the clutched position as illustrated in Figure 3it is clutched to the shaft 15 for rotation therewith. As the arm is nowmoved to the left, as viewed in Figure 3, against the force of spring 96to a position in which the apertures 95 are out of engagement with thepins 94, the arm I1 may be rotated. with respect to the shaft 15 and theclutch 90. A switch I is mounted in the path of movement of the cam 98,this switch including a movable arm IM and a fixed contact I02 isconnected to the fixed wall 19 by means of a bracket I03 and theinsulating material I04. The cam 98 and the switch arm IOI are sorelated with respect to one another that if the arm I1 is declutched androtated in a clockwise direction to a position in which both dampers Iand I6 are closed, the arm IOI will not be engaged by the cam 90. Shouldthe arm I1 be rotated past this position to a position in which thedraft damper I5 starts to open, cam 98 engages the arm IN and forces itagainst the fixed contact I02 for a purpose to be later described.

Also mounted on the walls 18 and 19 is the insulating member I05 onwhich is mounted the switch arm I06 which normally engages a fixedcontact I01 as illustrated in Figure 1. on the shaft 15 is a cam I09which engages a cam surface I08 ofthe arm I06 causing it to move out ofengagement with the contact I01 upon rotation of the shaft to a positionin which the arm I1 is in the draft producing position, that is, thecheck damper I6 is closed and the draft damper i5 is open. F

For supplying power to the blower motor 21 and the damper motor 10,lines H0 and III areprovided, these lines being connected to a suitableA step-down transformer H2 is provided for supplying low voltage powerto the relay- 60, this transformer including a high tension primary II3connected by. means of conductors I I4 and H5 to the lines lishedthrough. the winding I3 as follows: from the line H through conductorI30, switch arm I21, contact I29, conductors I3I, I60, contact I02,switch arm IOI, conductors I6I, I36, I31, switch arm I06,-contact I01,conductor I38, winding 13 and conductors I39 and I60 to the line III.Current also flows through winding I I by the following circuit: fromline IIIl, conductor I30,

switch arm 'I 21, contact I29, conductors I3-I, I60,

the amount of manual rotation of arm I1 or until pins 94 and apertures95 are in registry, the spring 96 will cause reclutching of arm I1 andthe shaft 15 which in turn causes the cam 93 to move out of engagementwith the switch arm- IOI which breaks the above described circuitsthrough the windings 13 and Id. If the room thermostat is stillsatisfied at this time, that is, it is not calling for heat, there willbe no circuit through the windings 14 and 13 and the spring 86 willcause arm I1 to move back to its draft retarding position. It will. thusbe seen that the operator may not manually move arm I1 beyond the firingposition toward the draft producing position while the room thermostatis satisfied and have it remain in this position since the damper motorwill immediately take control of the arm I1 and cause it to move back toits original draft retarding position.

While it is intended that the operator movethe arm I1 back to its draftretarding position become reestablished and cause shaft 15 to rotateuntil the arm I1 is clutched with the shaft 15 and the arm will be movedto its draft producing position as originally described.

It will be apparent that if the dampers are in their draft producingpositions caused by a lowered temperature in the space being heated andtheattendant desires to fire the furnace, the arm I1 may be manuallymoved back to its intermediate position' in the same way as from thedraft retarding to the firing position. Should the attendant leave thedampers in this position there is no possibility of any danger to thefurnace since if the' temperature of the heating chamber rises to a highenough value the current through the holding coil 14 will be interruptedeither by reason of the opening of switch '34 or" the satisfaction ofthe thermostat 50 whereupon spring 86 will cause shaft 15 to move towardthe draft retarding position and after it has moved back to the firingposition it will be again clutched with the arm I1 whereupon the armwill also be moved to its draft retarding position.

Should it be desired to use the system for cir-- I I0 through conductorI30, switclrblade I21, contact I28, conductors I 65, I 51, contact 03,switch blade 68, conductor I52, terminals 3i, 32 of the -motor 21, andconductor I53 to the line III. Mm

tor 21 will continue to operate as long as switch blade 33' is inengagement with contact 08 or in other words, as long as relay 60 isdeenergized.

Should the temperature of the space drop below the predetermined value,the relay 60 will be energized as formerly described and switch blade 63will move out of engagement with contact 68 thus interrupting thecircuit through the motor 21. With the switch blade I 21 in engagementwith contact I28 there will be no circuit through the damper motor 10and the dampers will be held in their draft retarding positions asillus= trated. I

Should there be an unseasonable cold spell during the summer time it maybe desirable to burn some trash in the furnace in order to raise thetemperature up enough tosupply the necessary heat to the space to bringthe temperature up to a comfortable point. In order to facilitate thecombustion of the trash the dampers should be moved to draft producingposition. This may be done by declutching the arm I1 from the shaft 15*and manually moving the same to a position in which the check damper isclosed and the draft damper is open. In this position of the arm I1 itwill be understood that switch arm MI is in engagement ,with contactI02. The temperature of the heating chamber will rapidly rise to a pointwherein the switch 35 will move to closed position. Acircuit includingthis switch is now established through the lifting winding 13 of themotor 10, this circuit being as follows: from line IIO through conductorI30, switch blade I21,

contact I28, conductors I65, I56, contacts 44 and 45 of switch 35,conductors I55, I32, I60, contact I02, switch blade IOI, conductors I6I,I36,

I31, switch arm I06, contact I01, conductor I38, -winding 13, conductorsI39 and I40 to the line II I. The holding winding 14 is also energizedthrough the following circuit: from line IIO through conductor I30,switch blade I 21, contact I28, conductors I65, I56, contacts 44 and 45of switch 35,'conductors I55, I32, I60, contact I02, switch blade IOI,conductors I6I, I36, I, winding 14 and conductor I40 to line III. Themotor will not rotate until the arm I1 becomes clutched with the shaft15 which takes place when the shaft 15 has rotated to a position inwhich the pins 94 and apertures 95 are in registry with one another,whereupon spring 96 moves arm I1 into clutching relationship with shaft15, whereupon the switch arm IOI moves away from contact I02.

No current now flows through either the winding I 13 or 14 of the motor10 and the spring 86 causes the shaft 15 and the arm I1 to rotate backto the draft retarding position.

When the switch 35 tilts to its closed position, the motor 21 isenergized, regardless of the position of the thermostat, the circuitthrough the motor 21 with the thermostat calling for heat being asfollows: from the line IIO through conductor I 30, switch arm I21,contact I28, conductors I65, I56, contacts 44 and 45 of switch 35,conductors I55, and I50, contacts 38 and 31 of switch 33, it beingunderstood that this switch is closed when the switch 35 is closed,conductor I5I, contact 61, Switchblade 64, conductor I52, terminals 3Iand 32 of motor 21 and conductor I53 to the line I I I. If thethermostat is not call- .ing for heat, the motor will be energizedthrough the previously described circuit, which circuit is independentof switch 35. It should be noted at Operation With the parts asillustrated the room thermostat 50 is satisfied, that is, it is notcalling for heat. The draft damper I and the check damper I 6 are in thedraft retarding positions, motors 21 and 10 are both deenergized and noair is being circulated by blower 25 through, the furnace and thespacebeing heated. Let it be assumed now that the temperature in thespace being heated. J

'tion of relay 60 causes blades 63, 64,and 65 to move into engagementwith contacts 66, 61, and 69, respectively. Engagement of blade 63 withcontact 66 closes a holding circuit for the coil 6| which is independentof the arm 53, this circuit being as follows: from the secondary I I6throughconductor I20, contact 54, arm 52 through the bimetallic element5|, conductor I24, contact 66, blade 63, conductors I25,- I22, coil 6Iand conductor I23 to the other side of the secondary II6. Since therelay coil 6I remains energized until the arm 52 moves away from contact54 'it will be understoodthat' the-coil 6| is deener'gized at a highertemperature than that at which it became energized, I

Movement of blade 65 into engagement with contact 69 causes theoperation of the damper motor 10. The lifting coil 13 of said motor isenergized, through the following circuit: from theline IIO throughconductor I3Il, switch arm I21, contact I29, conductors I3I, I32, I33,con--- tact 42 through the" mercury element 40 to the contact 4|conductor I34, switch blade 65, contact 69, conductors I35, I36, I31through the switch arm I06, contact I01, conductor-I38 through thewinding 13 and conductors I39 and m to the line I I I. Current alsoflows through the holding c'oil 14 as follows: from-the line, I I0,conductor I30,

switch blade I21, contact I29, conductors I3I, I32,

I33 switch 34 ,-conductor I34, switch blade 65, contact 69, conductorsI35, I36, I4I through the wihding 14 andconductor I40 to the line' III.The armature 12 now starts to rotate causing ro tation of shaft 15 insuch a direction that arm I1, as illustrated in Figure 1', is moved in aclockwise direction. This rotation continues until the check damper I6is closed and the draft damper I5 is opened at which time the pin 3|engages. the stop 82 and the cam I09 causes switch-arm I06-to move outof engagement with the' contact I01. Since this switch blade I06 is inthe-circuit through the lifting-winding 13 it is obvious the currentwill no longer flow through this winding. The current through thewinding" is just sufficient to counteract-the effect of spring 86 on arm85. so that said spring willnot cause rotation of ,arm I1 inacounter-clockwise direction as long as winding 14 remains energized.

Since the dampers have now'been moved to theirdraft producing positions,the rate of combustion in the furnace increases with an attendantincrease in temperature in theheati'ng chamher.

When the temperature reaches a certainhigh value, bimetallic element 23causes switch 33 to be tilted to a position in which contacts 31 and 38are bridged by the mercury element 36.

A circuit. is now established through the blower motor 2 1-which'circuitis as follows: from the line II 0 through conductor I30, switch bladeI21, contact I29, conductors I3I, I32, I50, contacts 38' tor 21 causesthe blower to circulate the air in the heating chamber through the spaceto be heated. Motor 21 will continue to operate until .the roomthermostat 50 has become satisfied, thus deenergizing the relay 60 andbreaking the circuit through the blower motor, or should the temperatureof the heating chamber fall below the value required to tilt the switch33 to closed position,

through the motor 21 to be interrupted.-

Should the temperature in the heating chamber rise to an excessive valueor to a value sufficient to cause switch 34 to tilt to open position,the aforedescribed circuit through the holding winding 14 of the dampermotor 10 will be interruptedsince this circuit includes the switch 34and the spring 86 will cause the damper operating arm 41 to move back tothe original position as illus- 4 the switch will be opened and causethe circuit trated and-.causethe dampers I5 and I6 to move in theirdraft retarding positions.

Should it so happen that the temperature of the heating chambercontinues to rise forv any reason after the room thermostat is satisfiedand the dampers are in their draft retarding positions, to a pointsufficient to cause switch to be tiltedto closed position, a circuitvwill be established through the motor 21 which is independent of theroom thermostat 50 so that this excessive heat inthe heating chamber maybe dissipated.

This circuit through the motor 2.1 is now as follows: from the-line IIOthrough conductor I30,

switch blade I21, contact I29,conductors I3I, I32,

I55, contactsj and 44, conductors I56, I51, contact 68, switch blade 64,conductor I52, terminals 3I and 32 of the motor 21 and conductor I53 tothe line H I., Motor 21 will thus continue to lustrated in Figure 1.. Ifnow it is desired to throw some fuel in the furnace, the check damper I6should be closed and the draft damper I5 should remain closed so thatwhen the door I1 is open'there will be a strong circulation of air overthe top of the fire and through the stack I2 to prevent' smoke, etc.from issuing out 'of' the door II. .In order to-move the damper I6 toits closed position the arm I1 may be moved inwardly or to the left asviewedin Figure 3 until apertures 95. and pins 94 are'out of engagementwith one another, whereupon the arm I1 may be rotated withrespect to theshaft 15. When so rotated the spring 86 exercises no effect whateverover the damper arm I1 sothat the arm will remainin the position inwhich it is placed as long as it is declutched from the shaft 15. Shouldthe attendant through mistake rotate arm I1 too far gage the contactI02. A circuit will now be estabthis point that motor 21 energizedwhenever switch 35 is tilted to closed position regardless of theposition of the summer-winter switch I26.

The. heat in the heating chamber of the furnace I is now circulatedthrough the space being heated thus causing a rise in the temperature ofsaidspace and the motor 21 will continue to operate until thetemperature in the heating chamswitch- 35 is open, whereupon the motorwill stop.

The dampers l5 and I6 will remain permanently in their draft retardingposition when the switch I26 is in its summer position until such timeas the attendant manually moves them to their draft producing positions.

It will thus be seen that I have devised a damper control system for awarm air furnace vwherein the dampers are under the control of the roomthermostat and a switch responsive to temperatures of the heatingchamber of the furnace-and in which, should it be desired to fire thefurnace the dampers may be manually moved to an intermediate firingposition wherein both.

dampers are closed, but should the dampers be manually moved beyond thisintermediate position they will again be moved back to draft retardingposition, assuming" this was the position of the dampers before theywere manually moved to the firing position. It will also be seen thatwith my system the 'fan may be operated inthe summer time to circulateunheated air through the space which is-normally being heated in thewinter time when the temperature in said space rises above a desiredvalue, at which time the dampers are normally in their draft retardingpositions and remain in these positions unless they are manually movedto the draft producing positionswhen it is desired to start a fire inthe furnace and that they will be moved to their normal draft retardingpositions as soon as the temperature of the furnace rises above acertain 'predetermined value. It will also be seen that re-' gardless ofthe temperature of the space being supplied with heated or unheated airand regardless of the position of the summer-winter switch the blower 25will always be operated whenever the temperature of the furnace reachesan excessive high temperature thus preventing any possible danger byreason of the overheating of said furnace by distributing the heatthroughout the building being heated.

WhileI have illustrated and described a preferred form of myinvention,it will be apparent that it is capable of many modifications by thoseskilled in the art and I 'wish it to be understood that the invention.is limited only by the scope of the appended claims. a

I claim as my invention:

1. In a heating system, a furnace, damper means for controlling the rateof combustion .in

said furnace, actuating means responsive to 'the attainment ofpredetermined conditions for causing movement of saiddamper means todraft producing and draft retarding positions, meanswhereby control ofsaid actuating means over the damper means may be temporarily withdrawnand the damper means manually moved to 'an intermediate firing. positionregardless of the existing condition and without causing the operationof the actuating meansso that said damper means may-normally bemaintained in said firing position for any desired period of time, and

means responsive to manual movement of said damper means from draftretarding position, past firing position towards draft producingposition for restoring control of said actuating means over said dampermeans.

2. In a furnace, damper means for controllingthe rate of combustion insaid furnace, said damper means having a draft producing position, adraft retarding position, and an intermediate firing position, a motorfor moving said damper means from draft retarding to draft producingposition and holding the -damper means in draft producing position,biasing means for causing movement of said damper means motor so thatsaid damper means may normally be maintained in said-firing position forany de-| sired period of time and means responsive only to movement ofthe'damper means from draft retarding past firing position towards draftproducing position for restoring control of said motor and biasing meansover said damper means.

3. In a heating system, a furnace, damper means for controlling the rateof combustion in said furnace, said damper means being movable intodraft producing, a draft retarding and a' firing position, actuatingmeans for causing movement of said dampermeans into draft producing anddraft retarding positions, condition responsive means controlling saidactuating means, means whereby said dampermeans and said actuating meansmay be declutched and said damper .means manually moved to the firingposition without causing the operationof said actuating means so thatsaid damper means may normally be maintained in said'firing position forany desired period of time, mea ns responsive to the operation of saidactuating means by the condition responsive means for causing saidactuating means and said damper means to be reclutched, and meansresponsive only to declutching of said actuating means and damper meansand manual movementof said damper means from draftretar'ding position,past firing position towards draft producing position for causing directreclutching of said damper means and actuating means;

' 4.- A damper motor comprisinga drivingvshaft, a damper actuatingmember, clutch means between said shait and damper actuating member,said clutch means including means for holding the damper actuatingmember in a different axial position with respect to said shaft whensaid shaft and member are declutched, from the position when said shaftand. member are clutched,

switch means, circuit means whereby saidmotor .is energized in responseto actuation of said switch means, means normally holding said sponsiv'eonly to rotation of said damper actuat ing arm relative to said shaftthrough a distance great enough tocause damper means actuated thereby-tomove from draft retarding position toswitch means in inoperativeposition, means re-' shaft to cause reclutching of said shaft and damperactuating member.

5. in combination, a furnace, damper means for controlling the rate ofcombustion in said furnace, said damper means having a draft producingposition, a draft retarding position, and an intermediate firingposition, an actuator for said damper means, biasing means for saidactuator tending to move said actuator to a position in which saiddamper means is in draft retarding position, a motor for moving saidactuator relatively quickly against said biasing means to a position inwhich said damper means is in draft producing position, conditionresponsive means forcausing the energization and deenergization of saidmotor, means for declutching said damper means from said actuatorwhereby said aacaoee damper means may be manually moved to the firingposition, means responsive to movement of said actuator by reason ofenergization of said motor to cause said damper means and said actuatorto be reclutched, a switch for causing the energization of the motorindependently of said condition responsive means, and means responsiveto declutching of said damper means and movement of the same from draftretarding position past firing position towards draft producing positionfor causing closure of said switch and accordingly energization of saidmotor to effect reclutching of said damper means and actuator, saidswitch being so located as not to be closed by the manual declutchedmovement of said damper means to firing position.

' GEORGE D. BOWER.

